Method of heat treating wire



Jan. 27, 1942. J. STATZ ETAL METHOD OF HEAT: TREATING WIRE Filed July22, 1938 2 Sheets-Sheet 1 1 III Jail. 27, 1942. J. smz ETAL METHOD OFHEAT TREATING WIRE Filed Ju1 22, 1938 2 Sheets-SheetR m a m m J05EPH 14/SW/FT m1 JOHN, 57??- Patented Jan. 27, 1942 METHOD OF HEAT TREATING WIREJohn Statz and Joseph H. Swift, Worcester, Mass., assignors to TheAmerican Steel and Wire Company of New Jersey, a corporation of NewJersey Application July 22, 1938, Serial No. 220,799

1 Claim.

The present invention relates to a method of heat treating wire.

It is among the objects of the present invention to heat treat wire inan inexpensive but extremely eflicient manner.

Another object is to heat treat and cool wire in such manner thatoxidation will be prevented.

A further object resides in maintaining the wire in a straight andsubstantially horizontal path during the period of change in grainstructure resulting from heating so that no strains are set up in thewire during such a period.

Other objects and advantages will become apparent as the descriptionproceeds and reference is had to the accompanying drawings, in which:

Figure 1 is a side elevation of the present invention in combinationwith a heat treating furnace;

Figure 2 is a section on the line II-II of Figure 1;

Figure 3 is a section on the line IIIIII of Figure 1; and,

Figure 4 is a detailed section on the line IV-IV of Figure 3.

In the drawings, in which there is illustrated a type of apparatus forpracticing the present method of heat treating and coating wires, thenumeral l represents a conventional hearth type of furnace. In a processof heat treating wire, the furnace l is maintained at varyingtemperatures up to 1650 degrees Fahrenheit. As the wires leave thefurnace I, they are subjected to a cooling step when heat treating isbeing practiced.

There is provided adjacent the exit end of the furnace, a kettle furnace2 of conventional design upon which is positioned a kettle 3 adapted tocontain the cooling medium. The cooling medium may comprise a liquidsalt.

An auxiliary trough 4 is supported, in any conventional manner, withinthe kettle 3 and is provided with an opening 4 extending trans-- verselythereof. A feed pipe 5, having an opening adapted to communicate withthe opening 4 formed in the troughl, communicates with a pump 6 drivenby motor I for receiving the cooling medium and distributing the sameinto the kettle 3. Positioned on the vertical sides of the trough 4between guide plates l5 are a plurality of plates 8 having apertures 9through which the wires being treated are adapted to pass in the, samehorizontal plane. These apertured plates also maintain the desired levelof the cooling medium within said trough 4. The trough 4 is providedwith one or more openings 4 upon which rests cover plates 4 while, atthe outlet side of said kettle furnace 2, the trough 4 is provided witha'transversely extending opening 4'. These openings permit the coolingmaterial to 5 fall into said kettle 3 and, depending upon how many coverplates 4 are removed, the length of immersion of said wire within thecooling material is controlled. As shown in Figure 4, the coolingmaterial ,falls into the kettle 3 near the outlet end of said furnace 2and by controlling the length of immersion of the wire in the coolingmedium. As the cooling material flows through said openings 4 and/or 4,it passes into said kettle 3, through the pipe Ill into the container orkettle J3, and back through the pump for recirculation in the trough 4.fl'hereforepa more uniform temperature of the treating bath ismaintained. Any desired typeof heat resisting packing I! may be providedfor the joint be-"" tween the opening formed in the auxiliary trough 4and the pipe 5. The apertures 9 in the plates I may be substantially thesame diameter as the wires being fed from the furnace, or, if desired,may be considerably larger than the wire being quenched.

Positioned over the auxiliary trough 4 and extending from the exit endof .the furnace throughout the entire length of said trough 4 is a coverl4 adapted to retain a body of inert gas over the surface of the coolingmedium and thereby prevent oxidation of the surface of the molten metal.The inert gas is supplied to the cover by means of the pipe l6 connectedto the blower l6 which draws the inert gas from the heating furnace Ithrough pipe ll.

In the heat treating of wires, the surface frequently becomes scratchedor spotted due to abrasion between the sinker rolls or bars which leadthe wire or wires beneath the cooling medium. In order to eliminate thepossibility of spotting or scratching the wires, we provide, under thepresent invention, the pump 6 in a separate kettle off to one side ofthe drawing furnace for the purpose of circulating the cooling 5 mediumbeneath the wires being treated. While there is shown a separate kettleI 3 for receiving the cooling medium and pumpi, if desired, thisseparate kettle can be eliminated and the pump can be readily adapted toexisting apparatus.

The flow of the coolingmedium is controlled by the speed of the rotarypump 8 which delivers the cooling medium to the auxiliary trough 4 andthereby maintains a uniform temperature of the cooling medium throughoutthe entire length of the bath.

Furthermore, if desired, the length of immersion of the wires within thecoolant can be regulated by providing the auxiliary trough l withopenings in the bottom thereof at predetermined points which will permitthe coolant to pass therethrough and return to the pump chamber. Thecooling medium is circulated underneath the wires being treated, which,in the present invention, are maintained in a. straight andsubstantially horizontal path so as to eliminate any possibility oftheir becoming bent while being treated.

According to the teachings of the present invention, the wires beingtreated are submerged in a substantial body of coolant in the trough 4.Before entering the trough I, the wires are enveloped and surrounded bya body of heated inert gas, which prohibits any substantial cooling andalso any oxidation of the wires. The heated inert cooling of thecoolant, which can thereby be kept at a fairly uniform temperature and,at the same time, this inert gas prevents the contact of any air withthe coolant.

While we have shown and described a specific embodiment of the presentinvention, it will be understood that we do not wish to be limitedexactly thereto, since various modifications may be made to theinvention without departing from the scope thereof as defined by thefollowing claim.

We claim:

The method of treating wire which comprises heat treating the same,immersing the wire while still in a heated condition in a liquid coolingmedium in an inert atmosphere, and maintaining the wire in a straightand substantially horizontal path and in contact only with the liquidcooling medium during the treatment.

JOHN STATZ. JOSEPH H. SWIFT.

